[lelio]

but that does not prevent a passenger from doing the evil deed
Yikes I never even thought of that! Its probably easier that way as the staff talks amongst themselves and wouldn't be able to keep a secret. Anonymous passenger, doesn't know anyone on board, brings a vial. He's off the boat and the cruise line never hears from him again.

[antivenom]

This was a 4 day cruise!

YIKES!!!